Working with LRSocket, receiving

Report · Sep 22, 2015

I'm trying to set up a communication between Lightroom and another process using LRSocket. I've worked out an LrSocket.bind with mode = "send" and that's all working fine but I cannot for the life of me get a receive working. Here's my Lua code:

Connection = {

}

function Connection.Listen( self, context )

local running = true

self.Listener = LrSocket.bind {

functionContext = context,

port = 4242,

plugin = _PLUGIN,

mode = "receive",

onConnected = function( socket, port )

Debug.logn( "Listener connected on port " .. port )

end,

onMessage = function( socket, message )

Debug.logn( "Listener Got: " .. message );

end,

onClosed = function( socket )

Debug.logn( "Listener Closed on Port: " .. myPort )

running = false

end,

onError = function( socket, err )

if err == "timeout" then

end

end,

} -- bind

while running do

LrTasks.sleep( 1/2 ) -- seconds

end

self.Listener:close()

end

I've been testing with both telnet and a short python snippet shown below. Telnet fails to connect at all, the Python code connects and the onConnected callback is called but, although text is being sent, the onMessage callback doesn't get called. I wondered if anyone had managed to make this work at all or if anyone has any pointers on what might be going wrong.

import socket, select, sys, time

def Send( msg 😞

TCP_IP = 'localhost'

TCP_PORT = 4242

BUFFER_SIZE = 1024

MESSAGE = "Hello, World!"

print "Sending on port ", TCP_PORT

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

s.settimeout(2)

s.connect((TCP_IP, TCP_PORT))

s.send(MESSAGE)

print "Sent"

s.close()

time.sleep( 5 )

print "Closed"

Send( "Test")

Many thanks.

Report · Sep 22, 2015

I should add, I am calling all of this within a function context and a within an async task:

LrTasks.startAsyncTask( function()

LrFunctionContext.callWithContext( 'socket_send', function( context )

local Replier = Connection

Replier:Listen( context )

end)

Report · Sep 22, 2015

I have been trying to use the new LrSocket for communication back and forth with a visual basic .net program. I have been able to send a command to lightroom, but I cannot get lightroom to respond.

Make sure the command you send has a new line char at the end.

Here is the code I am using. This is based on some examples i saw somewhere. If someone could help me with the sending part. I cannot even get it to send to itself if I set the same port number.

local LrSocket = import "LrSocket"

local LrTasks = import "LrTasks"

local LrFunctionContext = import "LrFunctionContext"

local LrDialogs = import 'LrDialogs'

local LrApplication = import 'LrApplication'

local LrDevelopController = import 'LrDevelopController'

local LrSelection = import 'LrSelection'

LrLogger = import 'LrLogger'

myLogger = LrLogger( 'exportLogger' )

myLogger:enable( "print" )

-- Global consts

local RECEIVE_PORT = 9885

local SEND_PORT = 9886

-- Global vars

local SERVER = {}

function process_Mess (command)

dbgout(" Processing Mess")

--dbgout(command)

--LrDialogs.message( "Received Message", command, "info" );

posblank1 = string.find ( command, ' ', 1 )

if posblank1

then

LRfunc = string.sub ( command, 1, posblank1-1)

else

LRfunc = command

end

dbgout (" "..posblank1)

dbgout (LRfunc)

if LRfunc == "hello" then

dbgout (" Action: = Hello")

LrDialogs.showBezel( "Hello", 2 )

dbgout ("	Send Message")

SERVER:send( "Hello world \n" )

dbgout ("

Message Sent")

end

local function startServer(context)

SERVER = LrSocket.bind {

functionContext = context,

plugin = _PLUGIN,

port = SEND_PORT,

mode = 'send',

onClosed = function( socket )

end,

onConnecting = function( socket, port )

dbgout( "------- Server Waiting for Connection..")

dbgout( "------- Port: "..port)

end,

onConnected = function( socket, port )

dbgout( "------- Server Connected")

dbgout( "------- Port: "..port)

end,

onError = function( socket, err )

dbgout( "------- Server Error")

dbgout( err)

socket:reconnect()

end,

}

end

LrTasks.startAsyncTask( function()

LrFunctionContext.callWithContext( 'socket_remote', function( context )

dbgout("Socket Receive");

local running = true

local client = LrSocket.bind {

functionContext = context,

plugin = _PLUGIN,

port = RECEIVE_PORT,

mode = 'receive',

onMessage = function(socket, message)

dbgout("Message:=")

dbgout(message)

process_Mess(message)

end,

onConnecting = function( socket, port )

dbgout( "Waiting for Connection..")

end,

onConnected = function( socket, port )

dbgout( "Connected")

end,

onClosed = function( socket )

socket:reconnect()

dbgout( "Closed")

SERVER:close()

startServer(context)

end,

onError = function(socket, err)

if err == 'timeout' then -- reconnect if timed out

socket:reconnect()

end

}

startServer(context)

while true do

LrTasks.sleep( 1/2 )

end

client:close()

SERVER:close()

end )

Report · Sep 22, 2015

It was the new line. Thanks for that.

I can't see anything wrong with your code, maybe it's at the VB end. Did you try with telnet?

I'll post working code when I'm all tidied up and in good order in a couple of days.

Report · Sep 27, 2015

As promised, my working example of using LrSocket. It's Mac tested, should work for Windows but you'll need Python installed. It's a very simple send receive plugin, the Python script takes input from the terminal, sends it to the Lightroom plugin, the Lightroom plugin responds with a simple "OK". Start the plugin listening with File->Plugin Extras->Connection Test, kill it by sending it "exit" from the Python script. You can fire up either end first and it'll wait for a connection from the other end.

Code is reasonably well documented.

My understanding of sockets is workmanlike but not extensive, there may be better ways of doing this.

Plugin

Report · Jul 03, 2016

Hi, i'm trying to run your plugin and python script on windows 10 and i cant send or receive any messages. It's just not working. I also have my own plugin that support LrSocket and works on OSX but running it within windows just seems like nothing happens. I tried telnet and other tools to debug it. Nothing seems to see it. What is the Port that should be used? or maybe firewall is blocking it?

Report · Aug 10, 2016

Hi Matt, sorry, I only just caught your message:

Couple of thoughts:

The lightroom plugin always needs to be started first. It times out after 10-15 seconds so you need to be sharpish about getting the Python script going.

Anything you send must be terminated with a new line. Lightroom doesn't respond until it sees one.

Send & receive ports have to be different using LrSocket. So if you use telnet you'll need to instances, one for sending another, on another port, for receiving. I don't know why they did this, it annoying.

you should be able to see send and receive ports in the plugin code.

LrSocket documentation is OK but there's a lot left unsaid, as you can see from the above. It took me a while to get it going.

I'm only developing on Mac for the moment. I don't have much I can say about Windows. Sorry.

Report · Sep 09, 2021

@kimaldis could you please reattach the plugin using LrSocket as client and as server? I currently can use only one of the two LrSocket at a time.

Thanks!!

Report · Nov 10, 2021

@lorenzos78098366did you manage to make it work? It looks like that the "send" LrSocket is actually a server: I can't send any message, but it receives connections from netcat while it shouldn't be receiving anything...

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Working with LRSocket, receiving